The roadblasters yoke is the same, but the x-axis was locked down - so it was just a glorified steering wheel. You could prob add a pot and get it to rotate somehow...
I actually read in a reputable source that Atari was commissioned to design a tank simulator along the lines of Battlezone(KLOV says it is a legend. *shrug*). Apparently they were uncomfortable doing that and only worked on the one project.
Anyways, I also recently lost an auction for a whole roadblasters cab - so then I was looking at alternatives and twistygrips came up of course.
The plans for the twisty grip don't look too difficult - I got them yesterday before I even found this particular thread - my interest in building a star wars yoke is pretty strong. This seems like a viable solution. In them the narrator explains each step and gives really good tips - apparently its' gone through a rewrite recently. There are new and improved variations for parts. Construction looks like it would be a solid sat afternoon - might as well give it a shot!
I don't feel like shelling out $104 bucks for a used yoke I'd have to modify anyways - be it a genuine starwars or roadblasters, they'd both have to be retrofit somehow to work on a PC.